Diletti Gianfranco, Scortichini Giampiero, Scarpone Rossana, Gatti Giuseppe, Torreti Luigi, Migliorati Giacomo
Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Via Campo Boario, 64100 Teramo, Italy.
J Chromatogr A. 2005 Jan 14;1062(2):247-54. doi: 10.1016/j.chroma.2004.11.019.
A gas chromatographic (GC) method with mass spectrometry detection (MS) for the determination of eight polycyclic aromatic hydrocarbons (PAHs) in olive pomace oil has been developed. The oil was diluted with n-pentane and extracted by liquid-liquid partition with dimethyl sulphoxide (DMSO). After water addition and back-extraction with cyclohexane, a thin-layer chromatography on silica gel was performed as a further purification step. The PAHs spot was scraped off from the plate and the final extract was concentrated and analysed by GC-MS in full scan mode. The eight PAHs under investigation were determined in the presence of the corresponding labelled compounds added as internal standards to the sample at the beginning of the analytical process. The identified PAHs were then quantified by the isotope dilution methodology assuring the compensation of the concentration of each analyte for any variation in the sample preparation. The method precision was satisfactory with relative standard deviation (R.S.D.) values in the range 3.6-12.7% for all PAHs. The average recovery rates ranged from 69.0 to 97.5%. Accuracy was also calculated for benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene and benzo[ghi]perylene by analysing a certified reference material (CRM 458, coconut oil) with adequate results. All response curves exhibited a linear fit from 0.1 to 10 microg ml(-1) and the determination coefficients R2 were better than 0.9942. The limits of detection (0.1-0.4 microg kg(-1)) were acceptable when compared with the maximum permitted limit of 2 microg kg(-1) for each of the eight considered PAHs and 5 microg kg(-1) for the sum of the eight PAHs established by the Italian legislation. Measurement uncertainty was finally calculated identifying and quantifying the uncertainty components of the analytical process. The relative expanded uncertainties (Uc), expressed as percent values were in the range 8.5-11.4% thus appropriate for residues quantification in the range of concentrations considered in the present study.
已开发出一种气相色谱（GC）结合质谱检测（MS）的方法，用于测定橄榄果渣油中的8种多环芳烃（PAH）。该油用正戊烷稀释，并用二甲基亚砜（DMSO）进行液-液萃取。加水并用环己烷反萃取后，进行硅胶薄层色谱作为进一步的纯化步骤。从板上刮下PAH斑点，最终提取物浓缩后，通过全扫描模式的GC-MS进行分析。在分析过程开始时，向样品中添加相应的标记化合物作为内标，在此条件下测定所研究的8种PAH。然后通过同位素稀释法对鉴定出的PAH进行定量，以确保补偿样品制备过程中每种分析物浓度的变化。该方法的精密度令人满意，所有PAH的相对标准偏差（R.S.D.）值在3.6-12.7%范围内。平均回收率在69.0%至97.5%之间。通过分析有证标准物质（CRM 458，椰子油），还计算了苯并[k]荧蒽、苯并[a]芘、茚并[1,2,3-cd]芘和苯并[ghi]苝的准确度，结果良好。所有响应曲线在0.1至10μg ml(-1)范围内呈线性拟合，测定系数R2优于0.9942。与意大利法规规定的8种PAH中每种的最大允许限量2μg kg(-1)以及8种PAH总和的5μg kg(-1)相比，检测限（0.1-0.4μg kg(-1)）是可接受的。最后计算了测量不确定度，识别并量化了分析过程中的不确定度分量。以百分比表示的相对扩展不确定度（Uc）在8.5-11.4%范围内，因此适用于本研究中考虑的浓度范围内的残留量定量。
